1. Technical Field
The present disclosure relates to a verification circuit, and more particularly to a verification circuit for a phase change memory array.
2. Description of the Related Art
A Phase Change Memory (PCM) is a non-volatile memory with high speed, high capacity and low energy consumption, wherein a plurality of PCM cells of the PCM cell is formed by phase change material, such as chalcogenide etc. The phase change material can be switched between two states, a crystalline state and an amorphous state, with the application of heat, wherein the phase change material has different resistances corresponding to the crystalline and amorphous states respectively, and the resistances respectively represent different stored data.
In general, different writing currents are provided to heat a PCM cell to change its resistance, such that data can be stored into the PCM cell. Furthermore, for a PCM cell, it is necessary for a writing current to transform the PCM cell into a reset state. Therefore, a verification circuit for verifying a PCM array is desired, which is used to verify that the memory cells of the PCM array have been transformed from a non-reset state to a reset state.